I built my flooring from the main entrance using engineered click lock (7 ply layers). I'd like to build/add on to the flooring from the backside, rather than the conventional front lip. I tried a couple rows and it worked, but it took a lot more tapping and minor flaking of the joint. Can this be done? Should I quit trying this?

I have not run into one yet that I could not install backwards. In all sense-ability they have be be able to be installed backwards as we run into situations where one must install backwards on chopped up layouts. And yes it can be a tad more difficult as the back edge is not profiled as much...less to tap on. Just take it easy. Also try connecting the endjoints in a full row first, then install them all at the same time.

Experiment to see what works best. I would also try locking individual plank lengths by hand, and lightly tapping the end seam together.

A full rotating lock is way more difficult than that rotate or tap stuff.

You can really damage a rotating lock by tapping?beating it together.

"Tap stuff" is called Uniclic.

You can damage any profile "beating it together".